#region Copyright (c) 2007 Ryan Williams <drcforbin@gmail.com>
/// <copyright>
/// Copyright (c) 2007 Ryan Williams <drcforbin@gmail.com>
/// 
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
/// 
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
/// 
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
/// </copyright>
#endregion

using System;
using System.Collections.Generic;
using System.Text;

using Mono.Cecil;

namespace Obfuscar
{
	static class TypeNameCache
	{
		static Dictionary<TypeReference, string> nameCache = new Dictionary<TypeReference, string>( );

		/// <summary>
		/// Recursively builds a type name.
		/// </summary>
		/// <param name="builder">Builder the type name will be added to.</param>
		/// <param name="type">Type whose name is to be built.</param>
		static void BuildTypeName( StringBuilder builder, TypeReference type )
		{
			GenericParameter genParam = type as GenericParameter;
			if ( genParam != null )
			{
				builder.AppendFormat( "!{0}", genParam.Position );
			}
			else
			{
				GenericInstanceType genType = type as GenericInstanceType;
				if ( genType != null )
				{
					builder.AppendFormat( "{0}.{1}<", genType.Namespace, genType.Name );
					for ( int i = 0; i < genType.GenericArguments.Count; i++ )
					{
						TypeReference argType = genType.GenericArguments[i];

						if ( i > 0 )
							builder.Append( ',' );

						BuildTypeName( builder, argType );
					}
					builder.Append( ">" );
				}
				else
				{
					ArrayType arrType = type as ArrayType;
					if ( arrType != null )
					{
						BuildTypeName( builder, arrType.ElementType );
						builder.Append( "[]" );
					}
					else
						builder.Append( type.FullName );
				}
			}
		}

		/// <summary>
		/// Builds a name for a type that can be used for comparing types.  Any generic parameters
		/// are replaced with their placeholder names instead of actual names (e.g., changes T to !0).
		/// </summary>
		public static string GetTypeName( TypeReference type )
		{
			string name;
			if ( !nameCache.TryGetValue( type, out name ) )
			{
				StringBuilder builder = new StringBuilder( );
				BuildTypeName( builder, type );
				name = builder.ToString( );

				nameCache[type] = name;
			}

			return name;
		}
	}
}
